Turn knob switch with removable luminous boot



United States Patent() "ice TURN KNOB SWITCH WITH REMOVABLE LUMINOUS BOOT Victor R. Despard, Syracuse, N. Y., assignor to Pass & Seymour, Inc., Syracuse, N. Y., a corporation of New Yor Application December 2, 1955, Serial No. 550,684

Claims. (Cl. 200-172) This invention relates to electric switches of the concealed wall type such as used in homes and oflices and more particularly to such switches having an operating knob adapted for partial rotation.

It is a general object of the present invention to provide a novel and improved turn knob switch with a removable boot which may be luminous at night.

An important specific object of the invention consists in providing a switch of the wall type with a partially rotatable actuating knob permanently attached to switch operating mechanism which latter is mounted in a switch housing having a separate front cover, the knob being small enough to pass through a hole in the cover and being fitted with a push-on boot increasing its gripping surface and too large to pass through the hole in the cover.

Another important object of the invention resides in the provisionof a boot of flexible, resilient material for engagement over a switch knob of frusto-conical form adapted to increase its gripping surface, offer a change of color and/ or night luminosity as well as provide condition indicating means of greater visibility.

A further object of the invention resides in the provision of a fluted switch knob of slightly tapered configuration having a substantially circular flat outer end provided with a position marker continuing over the side of the knob and of a resilient boot having similar marker means, together with internal ribs positioned to engage in said flutes to associate the knob and boot with the markers aligned.

Other and further objects of the invention will be more apparent to those skilled in the art upon a consideration of the accompanying drawing and following specification wherein are disclosed two exemplary embodiments of the invention, with the understanding that such changes and rearrangements may be made therein as fall within the scope of the appended claims without departing from the spirit of the invention.

In said drawings:

Fig. 1 is a longitudinal central section through a switch constructed in accordance with the present invention;

Fig. 2 is a transverse central section through the switch, the knob boot being omitted;

Fig. 3 is a front elevation of one form of the switch shown Without the boot on the knob;

Fig. 4 is a front elevation of another form of the switch shown with the boot in position on the knob; and

Fig. 5 is a bottom plan view of the knob boot showing its indicating rib and its internal knob indexing and drawing splines.

In my Patent 2,697,142 for Snap Switch with Oscillating Knob, granted December 14, 1954, I have shown a wall switch of the A.-C. type in which the movable contacts are engaged or disengaged by a partial rotation of an operating knob on the front face of the switch which extends through the wall plate. The present invention constitutes an improvement in the knob mechanism for that switch.

2,787,691 Patented Apr. 2, 1957 ent invention are identical with the same numbered figures in that patent, and reference should be had thereto for the electrical features and the actual internal operational devices therefor. For the purpose of the present invention it is suflicient to say that the switch mechanism is housed in a closed bottom molded synthetic housing 10 open at the top and provided with a one piece molded cover 11 secured thereon by any suitable clamping means such as the yoke 12. This cover has a protruding neck 13 which is rectangular in plan as seen at 14 to be received and clamped in a supporting bridge or strap device for holding it supported in an outlet box.

Surmounting the rectangular neck 14 in the embodiment of Figs. 1 to 3 is a platform or filler 15 for closing the opening in a Despard Line style wall plate. ThlS platform is of considerable width and length and is centrally provided with a circular bore 16 extending through the whole neck to rotatably accommodate the cylindrical shank 17 of the switch operator, which has the metal extension 18' pivoted in the bottom wall of the housing at 19 and adapted upon partial rotation to actuate the switch contacts as described in the patent mentioned above. An integral collar 20 engaging in the counterbore 21 in the cover 11 prevents withdrawal of the operator by manipulation of its knob 22 which projects beyond the face of the platform 15 to be grasped by the fingers for rotation to an angle of the order of 30 to turn the switch from the on to the off position and vice versa.

The knob 22 is preferably molded of insulating material integral with the parts 17 and 20 and of sufiiciently small diameter to be passed through the bore 16 in the cover. Its sides are provided with a slight taper as shown at 23 not only to facilitate its draft from the mold but to improve its appearance and these tapered sides are longitudinally channelled or fluted as seen at 24, adjacent flutes being separated by a common arris 25 all to facilitate grasping and rotating the rather small object which is shown twice actual size in the drawing.

The outer end 26 of the knob is flat with rounded corners 27 where it merges with the sides. The top is surmounted by an index device or pointer having the unique shape illustrated in Fig. 3 including the circular head 28 at its rear end and the elongated pointer portion 29 extending therefrom to and over the rounded edge 27 and down along the side of the knob as at 30, where it cooperates with the double pointed arrow 32 molded on the surface of the platform 15 to indicate the on and off position of the switch, or in the case illustrated to which one of the on positions'the mechanism is set, the switch being what is commercially known as a three-way or lazy mans switch, but actually comprising a single pole double throw switch.

It will be appreciated that the diameter of the switch knob is seriously limited by the necessity for passing it through the bearing hole 16 in the cover and in order that those wishing a larger knob for grasping and/or to enable the knob color to be changed at will, and to be luminous if desired, a removable boot or cap 32 is applied thereto as seen in Figs. 1 and 4.

Such a boot is molded from some pliable and stretchable plastic which does not take a permanent set, such as polyethylene, and in general its internal diameter at the base is about the same as the external diameter of the knob at the top portion, thus as the cap or boot is pushed into position over the knob it is stretched to insure good tight engagement with the knob surface to prevent rotational slippage or longitudinal withdrawal. The inner surface of the boot does not slide easily on the material of the knob.

As seen in the drawings the boot on its exterior is nearly a duplicate of the knob configuration, having the deep flutes 40 meeting in relatively sharp arris 41, tapering from the bottom to top in somewhat the manner of the knob but having a rounded outer end 42, best seen in Fig. l, surmounted by a continuous tapered index rib 43 raised above its surface sufficiently to be felt in the dark. This rib continues down both sides of the knob as best seen in Fig. 5, one side broadening into the shallow rib 44 and the other narrowing into a rib 45 progressively more projecting toward the bottom to cooperate with the index 32 as seen in Fig. 4.

To further insure against relative rotation of the boot and knob during switching operations, the interior wall of the boot has, in diametric opposition, molded therein the pairs of ribs 48 properly spaced to be received in flutes in the knob. They are so arranged as to properly index the boot marker 43 with the corresponding marker 29 on the knob surface.

The boot must naturally be applied after the knob has been passed through the hole in the housing cover since it is of greater diameter, as clearly seen in Fig. 1. It may be impregnated with most any color in order to permit switch users to adjust the switch color as they change decorator colors in the room inwhich the switch is installed. Moreover the boot may be impregnated with phosphorescent or fluorescent material whereby it gives off sufficient glow at night to enable the switch to be located in the dark without difficulty. When the boot is pushed down fully over the knob, engagement of its under top surface with the index 29 terminates its movement with the bottom just clear of the surface of the platform 15 so that no appreciable gap appears at this point to mar the appearance.

In the embodiment illustrated in Fig. 4 a slightly modified form of switch platform face is illustrated in conjunction with a conventional wall plate 50 having a rectangular aperture 51 therein of the size normally intended to accommodate the lever of a toggle or tumbler switch, the border 52 being decorative about this opening. The platform 53 on the cover of the switch is sized to closely fit through opening 51 and be flush with the surface of border 52. The knob diameter and boot are identical in this switch as in the Despard Line type but reference should be had to the fact that the diameter of the widest portion of the boot is greater than the width of the aperture 51 in the plate so that switches must be installed and plates put in position before the boots are applied, which is not true in the case of Fig. 1 where the boot may be mounted on the knob during the factory switch as sembly prior to its being inserted in the bridge or the plate, since the openings in both of these are adequate to clear the skirt of the boot. Switches with platforms of the type illustrated at 53 in Fig. 4 are referred to as strap types and their mounting strap is formed integral therewith or at least permanently attached thereto for supporting a single switch in a single gang outlet box, and these switches must be shipped with the boots separate for application after the plate is in position.

It will thus be seen that the boot provides a number of added features which facilitate the operation of the switch. First it enlarges the overall diameter and provides better facilities for grasping the switch to operate it, second, it changes the feel ortexture and improves the warmth of the material, third, it permits changes in color without replacing the switch, fourth, it provides =luminosity, if desired, and fifth, it permits the index markto be enlarged in the form of a protruding rib extending down over the side of the boot better to cooperate with the indcx arrows on the surface of the platform in the face of the switch. This latter cannot be done with the knob which must pass through the circular hole in the cover.

I claim:

1. A switch having a housing for operating mechanism and a separate closure cover having a central hole therethrough, an operating knob connected to said mechanism, journalled in said hole, of lesser diameter than the hole externally of the cover and partially rotatable to actuate the switch, and a flexible, resilient boot slidably en gaged over and held by said knob to provide a gripping surface larger in diameter than said hole to facilitate grasping to rotate said knob.

2. The switch of claim 1 wherein said knob is longitudinally fluted and slightly tapered and the boot has its maximum internal diameter equal to the minimum external diameter of the knob and is provided internally with ribs disposed and adapted to fit in selected flutes in the knob.

3. The switch of claim 1 wherein said knob is longitudinally fluted, slightly tapered and has a substantially flat outer end, a position indicating rib on said end and continuing down the side of the knob between two flutes, and the boot has its outer surface fluted, a marker rib extending across the top of the boot and down one side thereof becoming progressively more projecting, and means to locate the boot on the knob with the several ribs in alignment.

4. The switch as defined in claim 3 wherein the surface of the housing cover is provided with a position designating index for cooperation with either the knob rib or the boot rib to determine the direction the knob must be turned to change the switch condition.

5. The switch of claim 1 arranged to have a platform on said closure extend through the opening in a face plate intended to receive a toggle or tumbler switch handle and wherein the knob is less in diameter than the width of the platform and the boot diameter is greater than said width.

References Cited in the file of this patent UNITED STATES PATENTS 992,009 Lang May 9, l9ll 1,197,926 Frank Sept. 12, 1916 2,697,142 Despard "a..-" Dec. 14, 1954 

